<?php
/////////////////////////////////////////////////////////////////
/// getID3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.audio.flac.php                                       //
// module for analyzing FLAC and OggFLAC audio files           //
// dependencies: module.audio.ogg.php                          //
//                                                            ///
/////////////////////////////////////////////////////////////////


getid3_lib::IncludeDependency(GETID3_INCLUDEPATH . 'module.audio.ogg.php', __FILE__, true);

/**
 * @tutorial http://flac.sourceforge.net/format.html
 */
class getid3_flac extends getid3_handler
{
    const syncword = 'fLaC';

    public function Analyze()
    {
        $info = & $this->getid3->info;

        $this->fseek($info['avdataoffset']);
        $StreamMarker = $this->fread(4);
        if ($StreamMarker != self::syncword) {
            return $this->error('Expecting "' . getid3_lib::PrintHexBytes(self::syncword) . '" at offset ' . $info['avdataoffset'] . ', found "' . getid3_lib::PrintHexBytes($StreamMarker) . '"');
        }
        $info['fileformat'] = 'flac';
        $info['audio']['dataformat'] = 'flac';
        $info['audio']['bitrate_mode'] = 'vbr';
        $info['audio']['lossless'] = true;

        // parse flac container
        return $this->parseMETAdata();
    }

    public function parseMETAdata()
    {
        $info = & $this->getid3->info;
        do {
            $BlockOffset = $this->ftell();
            $BlockHeader = $this->fread(4);
            $LBFBT = getid3_lib::BigEndian2Int(substr($BlockHeader, 0, 1));
            $LastBlockFlag = (bool)($LBFBT & 0x80);
            $BlockType = ($LBFBT & 0x7F);
            $BlockLength = getid3_lib::BigEndian2Int(substr($BlockHeader, 1, 3));
            $BlockTypeText = self::metaBlockTypeLookup($BlockType);

            if (($BlockOffset + 4 + $BlockLength) > $info['avdataend']) {
                $this->error('METADATA_BLOCK_HEADER.BLOCK_TYPE (' . $BlockTypeText . ') at offset ' . $BlockOffset . ' extends beyond end of file');
                break;
            }
            if ($BlockLength < 1) {
                $this->error('METADATA_BLOCK_HEADER.BLOCK_LENGTH (' . $BlockLength . ') at offset ' . $BlockOffset . ' is invalid');
                break;
            }

            $info['flac'][$BlockTypeText]['raw'] = array();
            $BlockTypeText_raw = & $info['flac'][$BlockTypeText]['raw'];

            $BlockTypeText_raw['offset'] = $BlockOffset;
            $BlockTypeText_raw['last_meta_block'] = $LastBlockFlag;
            $BlockTypeText_raw['block_type'] = $BlockType;
            $BlockTypeText_raw['block_type_text'] = $BlockTypeText;
            $BlockTypeText_raw['block_length'] = $BlockLength;
            if ($BlockTypeText_raw['block_type'] != 0x06) { // do not read attachment data automatically
                $BlockTypeText_raw['block_data'] = $this->fread($BlockLength);
            }

            switch ($BlockTypeText) {
                case 'STREAMINFO': // 0x00
                    if (!$this->parseSTREAMINFO($BlockTypeText_raw['block_data'])) {
                        return false;
                    }
                    break;

                case 'PADDING': // 0x01
                    unset($info['flac']['PADDING']); // ignore
                    break;

                case 'APPLICATION': // 0x02
                    if (!$this->parseAPPLICATION($BlockTypeText_raw['block_data'])) {
                        return false;
                    }
                    break;

                case 'SEEKTABLE': // 0x03
                    if (!$this->parseSEEKTABLE($BlockTypeText_raw['block_data'])) {
                        return false;
                    }
                    break;

                case 'VORBIS_COMMENT': // 0x04
                    if (!$this->parseVORBIS_COMMENT($BlockTypeText_raw['block_data'])) {
                        return false;
                    }
                    break;

                case 'CUESHEET': // 0x05
                    if (!$this->parseCUESHEET($BlockTypeText_raw['block_data'])) {
                        return false;
                    }
                    break;

                case 'PICTURE': // 0x06
                    if (!$this->parsePICTURE()) {
                        return false;
                    }
                    break;

                default:
                    $this->warning('Unhandled METADATA_BLOCK_HEADER.BLOCK_TYPE (' . $BlockType . ') at offset ' . $BlockOffset);
            }

            unset($info['flac'][$BlockTypeText]['raw']);
            $info['avdataoffset'] = $this->ftell();
        } while ($LastBlockFlag === false);

        // handle tags
        if (!empty($info['flac']['VORBIS_COMMENT']['comments'])) {
            $info['flac']['comments'] = $info['flac']['VORBIS_COMMENT']['comments'];
        }
        if (!empty($info['flac']['VORBIS_COMMENT']['vendor'])) {
            $info['audio']['encoder'] = str_replace('reference ', '', $info['flac']['VORBIS_COMMENT']['vendor']);
        }

        // copy attachments to 'comments' array if nesesary
        if (isset($info['flac']['PICTURE']) && ($this->getid3->option_save_attachments !== getID3::ATTACHMENTS_NONE)) {
            foreach ($info['flac']['PICTURE'] as $entry) {
                if (!empty($entry['data'])) {
                    $info['flac']['comments']['picture'][] = array('image_mime' => $entry['image_mime'], 'data' => $entry['data']);
                }
            }
        }

        if (isset($info['flac']['STREAMINFO'])) {
            if (!$this->isDependencyFor('matroska')) {
                $info['flac']['compressed_audio_bytes'] = $info['avdataend'] - $info['avdataoffset'];
            }
            $info['flac']['uncompressed_audio_bytes'] = $info['flac']['STREAMINFO']['samples_stream'] * $info['flac']['STREAMINFO']['channels'] * ($info['flac']['STREAMINFO']['bits_per_sample'] / 8);
            if ($info['flac']['uncompressed_audio_bytes'] == 0) {
                return $this->error('Corrupt FLAC file: uncompressed_audio_bytes == zero');
            }
            if (!empty($info['flac']['compressed_audio_bytes'])) {
                $info['flac']['compression_ratio'] = $info['flac']['compressed_audio_bytes'] / $info['flac']['uncompressed_audio_bytes'];
            }
        }

        // set md5_data_source - built into flac 0.5+
        if (isset($info['flac']['STREAMINFO']['audio_signature'])) {

            if ($info['flac']['STREAMINFO']['audio_signature'] === str_repeat("\x00", 16)) {
                $this->warning('FLAC STREAMINFO.audio_signature is null (known issue with libOggFLAC)');
            } else {
                $info['md5_data_source'] = '';
                $md5 = $info['flac']['STREAMINFO']['audio_signature'];
                for ($i = 0; $i < strlen($md5); $i++) {
                    $info['md5_data_source'] .= str_pad(dechex(ord($md5[$i])), 2, '00', STR_PAD_LEFT);
                }
                if (!preg_match('/^[0-9a-f]{32}$/', $info['md5_data_source'])) {
                    unset($info['md5_data_source']);
                }
            }
        }

        if (isset($info['flac']['STREAMINFO']['bits_per_sample'])) {
            $info['audio']['bits_per_sample'] = $info['flac']['STREAMINFO']['bits_per_sample'];
            if ($info['audio']['bits_per_sample'] == 8) {
                // special case
                // must invert sign bit on all data bytes before MD5'ing to match FLAC's calculated value
                // MD5sum calculates on unsigned bytes, but FLAC calculated MD5 on 8-bit audio data as signed
                $this->warning('FLAC calculates MD5 data strangely on 8-bit audio, so the stored md5_data_source value will not match the decoded WAV file');
            }
        }

        return true;
    }

    private function parseSTREAMINFO($BlockData)
    {
        $info = & $this->getid3->info;

        $info['flac']['STREAMINFO'] = array();
        $streaminfo = & $info['flac']['STREAMINFO'];

        $streaminfo['min_block_size'] = getid3_lib::BigEndian2Int(substr($BlockData, 0, 2));
        $streaminfo['max_block_size'] = getid3_lib::BigEndian2Int(substr($BlockData, 2, 2));
        $streaminfo['min_frame_size'] = getid3_lib::BigEndian2Int(substr($BlockData, 4, 3));
        $streaminfo['max_frame_size'] = getid3_lib::BigEndian2Int(substr($BlockData, 7, 3));

        $SRCSBSS = getid3_lib::BigEndian2Bin(substr($BlockData, 10, 8));
        $streaminfo['sample_rate'] = getid3_lib::Bin2Dec(substr($SRCSBSS, 0, 20));
        $streaminfo['channels'] = getid3_lib::Bin2Dec(substr($SRCSBSS, 20, 3)) + 1;
        $streaminfo['bits_per_sample'] = getid3_lib::Bin2Dec(substr($SRCSBSS, 23, 5)) + 1;
        $streaminfo['samples_stream'] = getid3_lib::Bin2Dec(substr($SRCSBSS, 28, 36));

        $streaminfo['audio_signature'] = substr($BlockData, 18, 16);

        if (!empty($streaminfo['sample_rate'])) {

            $info['audio']['bitrate_mode'] = 'vbr';
            $info['audio']['sample_rate'] = $streaminfo['sample_rate'];
            $info['audio']['channels'] = $streaminfo['channels'];
            $info['audio']['bits_per_sample'] = $streaminfo['bits_per_sample'];
            $info['playtime_seconds'] = $streaminfo['samples_stream'] / $streaminfo['sample_rate'];
            if ($info['playtime_seconds'] > 0) {
                if (!$this->isDependencyFor('matroska')) {
                    $info['audio']['bitrate'] = (($info['avdataend'] - $info['avdataoffset']) * 8) / $info['playtime_seconds'];
                } else {
                    $this->warning('Cannot determine audio bitrate because total stream size is unknown');
                }
            }

        } else {
            return $this->error('Corrupt METAdata block: STREAMINFO');
        }

        return true;
    }

    private function parseAPPLICATION($BlockData)
    {
        $info = & $this->getid3->info;

        $ApplicationID = getid3_lib::BigEndian2Int(substr($BlockData, 0, 4));
        $info['flac']['APPLICATION'][$ApplicationID]['name'] = self::applicationIDLookup($ApplicationID);
        $info['flac']['APPLICATION'][$ApplicationID]['data'] = substr($BlockData, 4);

        return true;
    }

    private function parseSEEKTABLE($BlockData)
    {
        $info = & $this->getid3->info;

        $offset = 0;
        $BlockLength = strlen($BlockData);
        $placeholderpattern = str_repeat("\xFF", 8);
        while ($offset < $BlockLength) {
            $SampleNumberString = substr($BlockData, $offset, 8);
            $offset += 8;
            if ($SampleNumberString == $placeholderpattern) {

                // placeholder point
                getid3_lib::safe_inc($info['flac']['SEEKTABLE']['placeholders'], 1);
                $offset += 10;

            } else {

                $SampleNumber = getid3_lib::BigEndian2Int($SampleNumberString);
                $info['flac']['SEEKTABLE'][$SampleNumber]['offset'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));
                $offset += 8;
                $info['flac']['SEEKTABLE'][$SampleNumber]['samples'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 2));
                $offset += 2;

            }
        }

        return true;
    }

    private function parseVORBIS_COMMENT($BlockData)
    {
        $info = & $this->getid3->info;

        $getid3_ogg = new getid3_ogg($this->getid3);
        if ($this->isDependencyFor('matroska')) {
            $getid3_ogg->setStringMode($this->data_string);
        }
        $getid3_ogg->ParseVorbisComments();
        if (isset($info['ogg'])) {
            unset($info['ogg']['comments_raw']);
            $info['flac']['VORBIS_COMMENT'] = $info['ogg'];
            unset($info['ogg']);
        }

        unset($getid3_ogg);

        return true;
    }

    private function parseCUESHEET($BlockData)
    {
        $info = & $this->getid3->info;
        $offset = 0;
        $info['flac']['CUESHEET']['media_catalog_number'] = trim(substr($BlockData, $offset, 128), "\0");
        $offset += 128;
        $info['flac']['CUESHEET']['lead_in_samples'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));
        $offset += 8;
        $info['flac']['CUESHEET']['flags']['is_cd'] = (bool)(getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1)) & 0x80);
        $offset += 1;

        $offset += 258; // reserved

        $info['flac']['CUESHEET']['number_tracks'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));
        $offset += 1;

        for ($track = 0; $track < $info['flac']['CUESHEET']['number_tracks']; $track++) {
            $TrackSampleOffset = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));
            $offset += 8;
            $TrackNumber = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));
            $offset += 1;

            $info['flac']['CUESHEET']['tracks'][$TrackNumber]['sample_offset'] = $TrackSampleOffset;

            $info['flac']['CUESHEET']['tracks'][$TrackNumber]['isrc'] = substr($BlockData, $offset, 12);
            $offset += 12;

            $TrackFlagsRaw = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));
            $offset += 1;
            $info['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['is_audio'] = (bool)($TrackFlagsRaw & 0x80);
            $info['flac']['CUESHEET']['tracks'][$TrackNumber]['flags']['pre_emphasis'] = (bool)($TrackFlagsRaw & 0x40);

            $offset += 13; // reserved

            $info['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points'] = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));
            $offset += 1;

            for ($index = 0; $index < $info['flac']['CUESHEET']['tracks'][$TrackNumber]['index_points']; $index++) {
                $IndexSampleOffset = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 8));
                $offset += 8;
                $IndexNumber = getid3_lib::BigEndian2Int(substr($BlockData, $offset, 1));
                $offset += 1;

                $offset += 3; // reserved

                $info['flac']['CUESHEET']['tracks'][$TrackNumber]['indexes'][$IndexNumber] = $IndexSampleOffset;
            }
        }

        return true;
    }

    /**
     * Parse METADATA_BLOCK_PICTURE flac structure and extract attachment
     * External usage: audio.ogg
     */
    public function parsePICTURE()
    {
        $info = & $this->getid3->info;

        $picture['typeid'] = getid3_lib::BigEndian2Int($this->fread(4));
        $picture['type'] = self::pictureTypeLookup($picture['typeid']);
        $picture['image_mime'] = $this->fread(getid3_lib::BigEndian2Int($this->fread(4)));
        $descr_length = getid3_lib::BigEndian2Int($this->fread(4));
        if ($descr_length) {
            $picture['description'] = $this->fread($descr_length);
        }
        $picture['width'] = getid3_lib::BigEndian2Int($this->fread(4));
        $picture['height'] = getid3_lib::BigEndian2Int($this->fread(4));
        $picture['color_depth'] = getid3_lib::BigEndian2Int($this->fread(4));
        $picture['colors_indexed'] = getid3_lib::BigEndian2Int($this->fread(4));
        $data_length = getid3_lib::BigEndian2Int($this->fread(4));

        if ($picture['image_mime'] == '-->') {
            $picture['data'] = $this->fread($data_length);
        } else {
            $picture['data'] = $this->saveAttachment(
                str_replace('/', '_', $picture['type']) . '_' . $this->ftell(),
                $this->ftell(),
                $data_length,
                $picture['image_mime']);
        }

        $info['flac']['PICTURE'][] = $picture;

        return true;
    }

    public static function metaBlockTypeLookup($blocktype)
    {
        static $lookup = array(
            0 => 'STREAMINFO',
            1 => 'PADDING',
            2 => 'APPLICATION',
            3 => 'SEEKTABLE',
            4 => 'VORBIS_COMMENT',
            5 => 'CUESHEET',
            6 => 'PICTURE',
        );
        return (isset($lookup[$blocktype]) ? $lookup[$blocktype] : 'reserved');
    }

    public static function applicationIDLookup($applicationid)
    {
        // http://flac.sourceforge.net/id.html
        static $lookup = array(
            0x41544348 => 'FlacFile', // "ATCH"
            0x42534F4C => 'beSolo', // "BSOL"
            0x42554753 => 'Bugs Player', // "BUGS"
            0x43756573 => 'GoldWave cue points (specification)', // "Cues"
            0x46696361 => 'CUE Splitter', // "Fica"
            0x46746F6C => 'flac-tools', // "Ftol"
            0x4D4F5442 => 'MOTB MetaCzar', // "MOTB"
            0x4D505345 => 'MP3 Stream Editor', // "MPSE"
            0x4D754D4C => 'MusicML: Music Metadata Language', // "MuML"
            0x52494646 => 'Sound Devices RIFF chunk storage', // "RIFF"
            0x5346464C => 'Sound Font FLAC', // "SFFL"
            0x534F4E59 => 'Sony Creative Software', // "SONY"
            0x5351455A => 'flacsqueeze', // "SQEZ"
            0x54745776 => 'TwistedWave', // "TtWv"
            0x55495453 => 'UITS Embedding tools', // "UITS"
            0x61696666 => 'FLAC AIFF chunk storage', // "aiff"
            0x696D6167 => 'flac-image application for storing arbitrary files in APPLICATION metadata blocks', // "imag"
            0x7065656D => 'Parseable Embedded Extensible Metadata (specification)', // "peem"
            0x71667374 => 'QFLAC Studio', // "qfst"
            0x72696666 => 'FLAC RIFF chunk storage', // "riff"
            0x74756E65 => 'TagTuner', // "tune"
            0x78626174 => 'XBAT', // "xbat"
            0x786D6364 => 'xmcd', // "xmcd"
        );
        return (isset($lookup[$applicationid]) ? $lookup[$applicationid] : 'reserved');
    }

    public static function pictureTypeLookup($type_id)
    {
        static $lookup = array(
            0 => 'Other',
            1 => '32x32 pixels \'file icon\' (PNG only)',
            2 => 'Other file icon',
            3 => 'Cover (front)',
            4 => 'Cover (back)',
            5 => 'Leaflet page',
            6 => 'Media (e.g. label side of CD)',
            7 => 'Lead artist/lead performer/soloist',
            8 => 'Artist/performer',
            9 => 'Conductor',
            10 => 'Band/Orchestra',
            11 => 'Composer',
            12 => 'Lyricist/text writer',
            13 => 'Recording Location',
            14 => 'During recording',
            15 => 'During performance',
            16 => 'Movie/video screen capture',
            17 => 'A bright coloured fish',
            18 => 'Illustration',
            19 => 'Band/artist logotype',
            20 => 'Publisher/Studio logotype',
        );
        return (isset($lookup[$type_id]) ? $lookup[$type_id] : 'reserved');
    }

}
